Sharpener for cutting instruments



C. C. DICKlNSON.

SHARPENER Fu CUTTING INSTRUMENTS.

APPLICATION FILED APR-2l 1920. y

Patented Sept. 27, 1921.

PN a m( .l 6 l EEE? CLOYD C. DICKINSON, OF (.'I-IIi'JAGrO, ILLINOIS.

SHARPENER FOR CUTTING INSTRUMENTS.

Specification of Letters Patent. K Patented Sept 27, 1921.

Application filed April 2, 1920. Serial No. 3170,65?.

To allwiomz't may concern.' y

Be it known that I, CLoYD C. DioKiNsoN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Sharpeners for Cutting Instruments, of which the following is a specification. p

My invention relates to grinders or sharpeners, more especially for sharpening cutting instruments, the invention being particularly useful as a Sharpener for dental instruments. It will be understood by those familiar with dentistry that dentists have a considerable variety of chisels or cutting tools, the shaiiks near the point being either straight or twisted in various directions to enable the dentist to make cuts in various directions and in locations which are difiicult of access. The cutting edges must, of course, be sharpened frequently, and the general object of my invention is to provide a tool by kwhich the dentist may true and sharpen his various cutting instruments readily and accurately. It is well known that practically all dentists have socall ed hand pieces.` These are provided with chucks which rotate at high speed and are adapted to grip the spindles or Shanks of burs, drills, etc. An object of my invention is to pro-vide a Sharpener so constructed that the dentist may utilize this hand piece for driving a grinding wheel by which his instruments may be truedl and sharpened. It is frequently difficult for a dentist to determine the proper angle for the cutting edge of his instrument, `and it is one of the purposes of my invention to enablehim to 'predetermine` such angle with accuracy. .Y

I obtain my objects by the mechanism illustra-ted liii the accompanying drawings in which- Figure 1 is a general perspective illustrating the method of construction andthe mannerl of use of my device.

Fig'. 2 is a side elevation of the device showinga dental instrument in position in it and the gage block in position upon the instrument.

Fig. 3 is a sectional view taken lengthwise of the central support or handle and'lengthwise'of the posts rwhich in use stand ap- `j[ roximately, upright.

Fig. 4 is a fragmentary detail showing lupoiifan enlarged scale the manner of using the gage' block.. l

Fig.. 5 is a fragmentary detail chiey in section. showing the gage block and the'clip by which it may be detachably held upon the instrument during the act of testing the Sharpener.

F ig. 6 is'a top view of the parts shown in Fig. 5.

Like numerals denote like parts throughout the several views.

In the particular design selected to illustrate the invention as applied to a Sharpener for dentists use, 1 represents the central support. This is here shown in the form of a bar, convenient to be held in the hand of the operator. At the 'opposite ends of the` support 1 are two normally upstanding, or approximately so. In the construction shownv the pivots are in they form of screw studs 6, 6 arranged parallel to zeach other and having knurled set nuts 7, 7 by which the posts may be fixed at any desired angle relatively to the cen'- tral support. The post 2 has a work holder block 8 swiveled to it in such mannerk that the axis of rotation extends lengthwise of the post. This effect is accomplished in the present instance by means of a cylindrical pin 10 formed atthe'free end of the post 2 and fitting into a socket 11 formed in the bottom Vof the block. The block is prevented from slipping off the pin by means of a set screw 12, the inner end of which enters the annular notch 14 formed in the side of `pin 10. The work holder block 8 has a transverse aperture 16 adapted to receive the shank of the dental instrument 17. A set screw 18 is provided at the'end ofthe holder block for clamping the instrument in place.

.The post 4 at the opposite end of support 1 is provided with a block 20 at its upper end which is swiveled to it as in the case o-f block 8. A pin 22 extends from post 4 into a socket 23 formed in block 20' and a set screw 24 is provided for fixing the position of the block 2O about its axis of rotation. The inner end of set screw 24 projects into an annular notch 25 formed in the side of pin 22 and prevents the block 2O from coming oil. j

At the upper end of block 20 is a bearing 28 in which is journaled a spindle 30. This bearing extends transverse to the block and hence when the parts are adjusted in the manner. shown in Fig. 2, the spindle will lie approximately in the plane of rotation of posts, 2, 4' which are Vpost 2;

post 4, although its position may be altered to suit conditions. A grinding element 32 is fastened to the inner end of the spindle and by pre-ference is in the form of a wheel having a flat grinding face. Spindle 30 is not only rotatable' in its bearing, but is slidable also, so that the grinding wheel may be moved forward and backward into and out of engagement with the point of the instrument without changing their angular relationship.

In order that the dentist may accurately adjust the various elements of the device so as to produce the proper bevel on the cutting edge of the instrument, I provide a gage block 36 having a clip 37 which may be slipped over the instrument and hold the block in position. By preference the faces of the block are arranged at different angles with respect to the clip, for example, 40 degrees and 60 degrees, thus affording the operator` a choice as to what angle he will produce.

In practice, when the invention assumes the form illustrated, the dentist first inserts the shank of the instrument 17 into the holder block 8 through the aperture 16. He then tightens up the set screw 18 and thus clamps the instrument in position. He next inserts the outer end of the spindle 30 into the chuck of his hand piece. rlhe hand piece is illustrated in Fig. 1 where the rotating chuck is represented by the numeral 40 and is shown journaled within the housing 41. The housing` occurs at the end of a flexible tubing 42 and within the tubing is a flexible shaft (not shown) which drives the chuck.

Either before or after inserting the spindle 30 into the chuck of the hand piece, the operator attaches the gage block 36 to the point of the instrument in order to assist him in determining the angles to which he should bring the various parts. It will be noted that he has a choice of at least four adjustments, viz., the positio-n of thepost 2 with respect to the support 1; the position of the post 4 with respect to the support 1; the position of the block 8 with respect to the and the position of the block 2O with respect to the post 4. By suitably availing himself of the various adjustments offered, the operator may obtain almost any angle desired, and when the adjustments have been made, the nuts and screws 7, 12 and 24 are tightened, the gage block removed, and the device is ready for use. It will be understood that the chuck of a dentistshand piece usually rotates at high speed, for example, from two or three thousand revolutions a minute to six thousand or more. When he is ready to actually sharpen the tool the dentist grasps the device in the manner suggestedV in Fig. 1 and gradually slides the rotating spindle along its bearings to bring the grinding wheel 32 into Contact with the point of the instrument. As the spindle and grinding wheel are rotating at high speed, a mere touch of the grinding wheel will usually be sufiicient to sharpen the instrument.

One of the reasons why my device is of such value is that with the grinding wheel rotating at as high speeds as are usually produced by dental hand pieces, the dentist, if unassisted by a device such as mine, would be very apt to cut away an excessive amount of the instrument, and furthermore, he would find it difficult, if not impossible, to hold the grinding wheel at the proper angle to produce the desired bevel. When assisted with my device, however, the angles can be previously arranged for and the dentist may brace his hands againstl the device and thus obtain absolute control over the movements of the wheel. The slightest touch of the grinding wheel against the instrument will usually be suiiicient for the purpose, thus not only saving the dentists time, but enabling him to remove only such' amount of metal as may-be necessary to properly sharpen the instrument. My device has another advantage, and that'is that if the dentist is using a particular instrument and finds that during the course of its use he must resharpen it, he can, by avoiding disturbing the adjustment of the device, reproduce the angle as many times as hewishes and with very little effort.

It will be noted that the device is extremely simple in construction and durable, and also that it occupies very little space and does not require to be clamped to a table or other stationary object. It is so small and light that it may be readily keptV in the tray of the operating table and may be used by the dentist without leaving his position or retiring to alaboratory or work room.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. A grinding tool having a support with two elements which are angularly adjustable with reference to each other, one of said elements being adapted to carry the instrument to be ground and the other having a journal bearing, a grinding wheel, and a spindle for said wheel which is both rotatable and .freely slidable in said bearing, whereby the wheel may be fed toward the instrument without altering their angular relationship. j

2. A grinding tool having a support, two elements which are angularly adjustable with reference to the support and to each other, one of said elements being adapted to carry the instrument to bel ground and the other having a journal bearing, means for fixing the position of said element in the desired angular positions, a grinding wheel located between saidtwo elements, and a spindle adapted to carry said grinding wheel, said spindle being rotatablel and freely slidable lengthwise in said bearing, whereby the wheel may be fed toward the instrument without altering their angular relationship.

3. A grinding wheel having a support, two upstanding posts pivoted to said support, means for Clamping said posts in different angular positions, one of said posts having a clamp for supporting the instrument to be ground, said clamp being adapted to permit endwise adjustment of the instrument, the second post having a journal bearing, a grinding wheel, and a spindle fastened to said wheel, said spindle being rotatable and longitudinally slidable in said bearing, the grinding wheel being located between the posts whereby the sliding of the spindle in its bearing brings the wheel toward and from the instrument to be ground, without changing the angular relationship.

4. A grinding tool for dental instruments having a. support provided with two upstanding posts pivotally connected to said support and having their axes parallel to eaeh other, an instrument holder provided with a clamp by which the instrument to be ground may be rigidly held, said instrument holder being artieulately connected to one of said posts and adapted tol rotate about an axis extending longitudinally thereof, a bearing mounted upon the remaining post, av spindle journaled and longitudinally slidable in said bearing, the bearing being adapted to hold the spindle approximately in the plane of rotation of said posts, a grinding wheel secured to said spindle between the posts, and means for rotating said spindle and simultaneously sliding it in its bearing t0 feed the wheel toward the work. Y

5. A grinding tool for dental instruments, having a support provided with two upstanding posts pivotally connected to said support and having their axes parallel to each other, an instrument holder provided with a clamp by which the instrumentv to be ground may be rigidly held, said instrument holder being mounted on one of said posts and adapted to rotate about an axis extending longitudinally thereof, a spindle journaled and freely slidable in said bearing, said bearing being adapted to hold the spindle approximately in the plane of rotation of said posts, a grinding wheel secured to said spindle between the posts, and driving means for rotating and sliding said spindle, said driving means and the tool being on opposite sides of the last mentioned block.

6. A grinder for dental instruments having a handle, two upstanding posts hinged to said handle about parallel axes, a clamp at the top of one of said posts for holding the instrument to be ground, a bearing at the top of the other of said posts, a spindle journaled in said bearing, and a grinding wheel fastened to said spindle between the posts, said spindle being longitudinally slidable in its bearing for bringing the wheel toward and from the point of the instrument.

In witness whereof, I have hereunto subscribed my name.

CLOYD C. DICKINSON. 

